In semiconductor device manufacturing apparatuses which form patterns on the order of sub-microns, it is necessary to reduce the amount of dust, the amount of contamination and the size (or capacity) of the apparatuses. This is because the major cause of device defects results from the dust discharged from the apparatus and its periphery. Thus, the manufacturing apparatus is placed in a clean room, thereby resulting in higher cost of construction and maintenance.
It is known in the prior art that mechanisms are needed to transfer a substrate between a plurality of process chambers of the semiconductor manufacturing apparatus, which are connected under different kinds of ambient conditions. One such example is disclosed in Japanese Published Application No. 19252 (1991). This semiconductor manufacturing apparatus is constructed of first and second vacuum chambers having transfer arms therein, process chambers communicating individually with the vacuum chambers, and a plurality of vacuum process chambers. This transfer mechanism technique has multiple built-up arms and is mounted in an vacuum isolation type apparatus which is designed to have evacuating means for establishing a vacuum pressure gradient in those chambers.
On the other hand, Japanese Published Application No. 252439 (1988) discloses a multi-stage transfer mechanism disposed in a multi-process chamber system, which includes a central transfer chamber having an R-.theta. transfer arm, and in which different wafers are subjected simultaneously to the processes of chemical gas etching, chemical gas deposition, physical sputtering and rapid thermal treatment. Alternatively, similar wafers are subjected to various treatments in order in a plurality of process chambers adjacent to the central transfer chamber and having a uniaxial receiving transfer arm.
Japanese Published Application No. 87785 (1992) discloses a transfer mechanism technique having a multi-stage built-up structure using geared belts and pulleys as a central transfer arm of a multi-chamber treatment apparatus.
Japanese Published Application No. 28047 (1988) discloses a technique for transferring substrates by using movable portable chambers and extending/contracting the arms of a multi-stage structure. The arms of the multi-stage structure are built-up with their joints coaxially intersecting. Transfer ports of common specifications are connected to each other.
Japanese Published Application Nos. 161608 (1987) and 87351 (1986) disclose a transfer mechanism technique of using "frogger" arms which are driven by a pair of coaxial joints and timing belts.
Japanese Published Application Nos. 278149 (1986) disclose another technique of using "frogger" arms which have a pair of coaxial joints.
Japanese Published Application No. 183736 (1985) discloses a transfer mechanism technique which uses a handler having a pair of coaxial joints and a gear-driven arm.
Japanese Published Application No. 294984 (1992) discloses a transfer mechanism technique which uses elastic arms made of band-shaped spring members but does not have any slide portion.
Japanese Published Application No. 206547 (1992) discloses a transfer mechanism technique which transfers substrates without breaking a sealed state of the ambient in a sealed enclosure by connecting the sealed enclosure with a common port and then by opening/closing the gate valves of the common port.
Japanese Published Application No. 15592 (1994) discloses a transfer mechanism technique using "frogger" arms having coaxial rotary joints at the leading ends of a set of arms. The arms are capable of extending/contracting in opposite directions and are capable of being mounted with two substrates.
Japanese Published Application No. 184678 (1985) discloses a transfer mechanism technique for a vacuum process apparatus composed of process dedicated stationary vacuum enclosures and transfer dedicated movable vacuum enclosures so as to transfer substrates by connecting the process dedicated vacuum enclosures to each other through a common control gate and by moving the transfer dedicated vacuum enclosures linearly or rotationally.